Because they're working across such a broad array of features and channels, many of today's phone systems are adopting the moniker of Unified Communications-as-a-Service (UCaaS). These are generally cloud-based, virtual PBXes (private branch exchanges) that include at least one (usually multiple) software clients to enhance their functionality on the web, desktop, and especially mobile devices. Even residential VoIP systems come with features that are simply impossible with a conventional telephone system.
Either way, a business voicemail system plays a large role alongside the daily operations of many companies. It helps employees maintain a structure to their inbound calls, and it filters messages into a reviewable stack. Moreover, voicemail can make a company look professional through the use of greetings that establish a basic relationship between caller and business.

What voice do you want to convey when speaking with customers? This may be professional, casual, or even humorous.
Whether you’re out for the day or are off for the week, the first rule of an out of office voicemail greeting is: let callers know when you’ll be back! You’ll save them the frustration of continuing to call and yourself the hassle of listening to redundant voicemails. It’s also a good idea to set the expectation of whether you are answering messages while you’re away, and who they can reach for assistance in your absence.